Visualization of nano-plasmons in graphene

We study localized plasmons at the nanoscale (nano-plasmons) in graphene. The collective excitations of induced charge density modulations in graphene are drastically changed in the vicinity of a single impurity compared to graphene's bulk behavior. The dispersion of nano-plasmons depends on the number of electrons and the sign, strength and size of the impurity potential. Due to this rich parameter space the calculated dispersions are intrinsically multidimensional requiring an advanced visualization tool for their efficient analysis, which can be achieved with parallel rendering. To overcome the problem of analyzing thousands of very complex spatial patterns of nano-plasmonic modes, we take a combined visual and quantitative approach to investigate the excitations on the two-dimensional graphene lattice. Our visual and quantitative analysis shows that impurities trigger the formation of localized plasmonic excitations of various symmetries. We visually identify dipolar, quadrupolar and radial modes, and quantify the spatial distributions of induced charges.     

Visualization of leakage flow in buildings

Leakage flow around a window has been visualized with the aid of holographic interferometry. The experiments were performed during winter.     

Visualization techniques in plasma numerical simulations

Numerical simulations of plasma processes usually yield a huge amount of raw numerical data. Information about electric and magnetic fields and particle positions and velocities can be typically obtained. There are two major ways of elaborating these data. First of them is calledplasma diagnostics. We can calculate average values, variances, correlations of variables, etc. These results may be directly comparable with experiments and serve as the typical quantitative output of plasma simulations. The second possibility is theplasma visualization. The results are qualitative only, but serve as vivid display of phenomena in the plasma followed-up. An experience with visualizing electric and magnetic fields via Line Integral Convolution method is described in the first part of the paper. The LIC method serves for visualization of vector fields in two dimensional section of the three dimensional plasma. The field values can be known only in grid points of three-dimensional grid. The second part of the paper is devoted to the visualization techniques of the charged particle motion. The colour tint can be used for particle’s temperature representation. The motion can be visualized by a trace fading away with the distance from the particle. In this manner the impressive animations of the particle motion can be achieved.     

Visualization of wave propagation in muffler

This paper presents a prediction technique for wave propagation in muffler using Boundary Element Method (BEM). The results of the numerical calculation are compared with the plane-wave theory and also the experimental results. It is shown that at high frequencies the plane-wave theory does not yield correct results due to the occurrence of two- and three-dimensional wave motion. On the other hand, the BEM is able to predict the acoustic wave behavior in the high frequencies where the planewave theory fails.     

Visualization of light propagation

Abramson has demonstrated that by using the finite coherence properties of light, holograms can be constructed that allow one to visualize the path that a simulated light pulse takes through an optical system. We have demonstrated that using an alternate hologram construction and readout geometry, light with a very long coherence length can also be used to visualize light propagation. Experimental results showing well resolved time-sequence photographs of reflection, refraction, and diffraction in an optical system are given.     

Visualization of the photorefractive grating in BSO

A technique based on self-imaging at finite conjugates has been experimentally demonstrated for visualization of laser-induced photorefractive gratings in BSO. A simple model theory has been used to provide the correct rules of geometrical optics of self-imaging. A novel technique has been used for photoinducing the periodic structure. An application has been made to determine the harmonic components of the nonsinusoidal refractive index modulation in the BSO for a grating period of 10 m and for external DC voltages of 6.0 and 3.0 kV. The technique is directly applicable to the visualization and study of laser-induced gratings (LIG) in thin nonlinear optical media.     

Visualization of neutrophil extracellular traps in TEM

Neutrophil extracellular traps (NETs) have recently been described as an important innate defence mechanism in inflammation. However, routine electron microscopic staining techniques faintly stain NETs and are therefore insufficient for enabling a distinction between these and the host cell debris as well as proteins regularly present at the site of inflammation. In order to test suitable electron microscopic staining techniques, NETs induced ex vivo via phorbol myristate were absorbed on formvar. Four types of drop-on-grid positive staining were used: osmium tetroxide (Os), osmium tetroxide-uranyl acetate-lead citrate (Os-U-Pb), ruthenium red-osmium tetroxide (RR-OsO4), and cuprolinic blue enhanced by sodium tungstate (CB-WO4). We observed no staining of NETs using Os, faint staining with Os-U-Pb, better but still weak staining with CB-WO4 and outstanding staining with RR-OsO4. Furthermore, RR-OsO4 staining also enables the observation of bacterial fimbriae-mediated adhesion, which is possibly responsible for the ability of NETs to bind bacteria. Thus, the offered RR-OsO4 staining technique may facilitate the study of the NETs-bacterial interactions.     

Visualization of ke V-ion-induced spikes in metals

Abstract

Using gliding averages, the density, temperature, and pressure evolution in a keV-ion induced spike in copper is presented. The particular event visualized has been selected since it represents the average features of ion-beam induced mixing. Equilibration between potential and kinetic energy in the molten spike core is discussed, emphasizing the role of the latent heat of melting. Re-fueling of heat to the spike by condensing adatoms is exemplified.     

Visualization of branch points in PT-symmetric waveguides

The visualization of an exceptional point in a PT-symmetric directional coupler (DC) is demonstrated. In such a system the exceptional point can be probed by varying only a single parameter. Using the Rayleigh-Schr?dinger perturbation theory we prove that the spectrum of a PT-symmetric Hamiltonian is real as long as the radius of convergence has not been reached. We also show how one can use a PT-symmetric directional coupler to measure the radius of convergence for non-PT-symmetric structures. For such systems the physical meaning of the rather mathematical term radius of convergence is exemplified.     

Visualization of super-compressibility in supersonic spiral-twisted jets

We have visualized first the super-compressibility and associated it phenomena in submerged under-expanded supersonic spiral-twisted gaseous jets during its flowing from the annular nozzle with a central cone. We have observed the regular unusual axial symmetric vortex structures of body rotation and chain structures of jets in argon, helium, nitrogen and air. The type of structure depends on geometry of nozzle and pressure in pre-chamber. Strong density gradient appears discretely in mentioned jets.